My invention relates generally to the subject matter disclosed in my copending application Ser. No. 001,600, filed Jan. 7, 1993, entitled "Scroll-Type Compressor Having Unidirectional Rotor". That application is assigned to the assignee of my present invention.
It is common practice in the refrigerant compressor art to mount within a fixed housing compressor pumping elements. The pumping elements may be in the form of axially movable compressor pistons driven by a rotary swashplate or a pair of involute scrolls that cooperate, one with respect to the other, to define a pair of pressure chambers. The swashplate in the case of an axially movable piston-type compressor, or the movable scroll in the case of a scroll-type compressor, is driven by a torque input driveshaft journalled at one end of the compressor housing. This normally requires the compressor housing to be formed with a stationary nose or mounting sleeve. A shaft bearing is mounted within an internally machined bearing pocket in the stationary sleeve. An inboard bearing also is provided for the rotor, thereby providing a straddle mounting for the shaft.
The bearing sleeve normally is provided with an externally machined bearing mounting surface for the purpose of supporting a rotary pulley hub. The pulley is driven by a belt that encircles a drive pulley connected to the engine crankshaft of a vehicle engine in the case of an automotive-type air conditioning system.
An electromagnetic clutch usually is mounted within the pulley, and the hub of the pulley acts as a core for electromagnetic clutch coil windings.
A clutch engagement plate is resiliently connected for axial shifting movement on the driveshaft in close proximity to a clutch plate having a friction surface carried by the pulley hub.
When the electromagnetic clutch is engaged, the engagement plate is brought into frictional driving engagement with respect to the pulley so that pulley torque can be distributed to the torque input driveshaft. When the electromagnetic clutch is disengaged, the engagement plate and the driveshaft to which it is connected are deactivated and remain stationary while the pulley continues to be driven by the engine crankshaft.
It has been found that this pulley and bearing arrangement is complex and costly because of the difficult machining operations that are required to maintain concentricity between the bearing for the driveshaft and the bearing for the pulley, the latter being radially disposed with respect to the former. This makes it difficult for such prior art compressors of a given capacity to be adapted for various engine sizes because the bearing arrangement and the electromagnetic clutch windings do not accommodate pulleys of various sizes.